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By M. Hardy

"The structural design of mine headframes is challenging due to the significant differences in the geometry, rigidity, and behaviour of these structures compared to conventional buildings. The differences are related to the main purpose of these structures, which is not human occupancy, but rather the support of hoisting equipment. The main objective of this paper is to present the seismic elastic behaviour of headframe structures in comparison with conventional buildings, which is the base case for the definition of seismic loads. This paper highlights the impact of backlegs on the dynamic behaviour of mine headframes, more specifically the resulting torsional sensitivity. INTRODUCTION The design of industrial structures is often governed by industrial processes rather than by architectural constraints. In ground-mounted hoisting plants, the structural configuration of headframes must allow clearances around conveyances and ropes while resisting the lateral loads associated with the hoisting equipment. Typically, these structures use backlegs to withstand the lateral loads, which leads to highly irregular structures with unconventional dynamic behaviour. The codes and standards applicable to the structural design of mine headframes in Canada are often incomplete or not adapted to the reality of practising engineers. This situation creates confusion, and engineers must look at various guidelines and international standards to support the engineering calculations required for the design of these structures. The loads resulting from the support of hoisting equipment, such as ropes and conveyances, are usually simple to calculate and are determined based on the information from manufacturer and industry related guidelines. Moreover, the loads associated with snow accumulation and wind are calculated applying the same methodology used for conventional buildings, without any major issues. On the other hand, the seismic loads are often difficult to calculate based on the methodology from the National Building Code of Canada due to the significant differences in the dynamic behaviour of the structures. The resulting structures may be either over-designed or worse, under-designed. Hence, there is a lack of uniformity in engineers’ designs. The latest edition of CSA S16-14 “Design of steel structures” includes Annex M (Informative) “Seismic design of industrial steel structures” to help designers close the gap between the requirements of traditional regulations and actual engineering practice."

Jan 1, 2019

By T. Kerr, C. Mattich, J. Wilson

"In refractory gold concentrates, gold is occluded in sulphide minerals preventing efficient cyanide leaching. Hence, roasting is used to oxidize sulphur and organic carbon, the latter being necessary to minimize recovery loss through the preg-robbing effect. In 2009, Outotec commissioned the circulating fluidized bed roaster at Syama gold mine in Mali. Since 2013 Resolute and Outotec have been implementing improvements to the roaster performance with the capacity increasing from 8000 t/month in 2013 to above 13,000 t/month in 2016, while achieving a residual sulphide sulphur and organic carbon contents of below 0.1 wt.% and 0.4 wt.%, respectively. Thus a gold recovery in the CIL of above 90% is attained. In 2016, Outotec audited the Syama roaster. The analysis resulted in the Low Carbon Roaster (LCR) upgrade concept which (i) allows re-processing of calcine dust from the spray cooler and ESP after pelletization and (ii) allows the roasting of a further fine-organic carbon rich feed, i.e. de-slime circuit tailings. The LCR upgrade aims to reduce organic carbon to <0.2 wt.% and increase roaster-leaching gold recovery by >3%. Project development included extensive testwork. The LCR process is expected to become operational during FY 2019.INTRODUCTION Double refractory sulphide ores exhibit the characteristics of gold locked within pyrite grains, in the presence of preg-robbing natural (organic) carbon. Hence, to achieve high recovery during subsequent processing steps, i.e. cyanide leaching, oxidation of sulphide sulphur is required, producing a porous calcine by way of a roasting step. This allows for the gold contained within the pyrite grains to be accessible during cyanide leaching. Furthermore, it is necessary to oxidize the organic carbon. Oxidizing the organic carbon is essential as gold recovery loss occurs as a result of gold-cyanide complexes being adsorbed on organic carbon, this phenomenon is termed as preg-robbing (Miller et al., 2016). The gold absorbed on the organic carbon is lost, reporting to the tailings stream. Hence, the aforementioned oxidation of sulphide sulphur and organic carbon is the process goal. Nonetheless, the latter must occur at a controlled temperature which is concentrate/ ore specific, since the pores of the produced calcine should not sinter, as this makes the gold contained in the calcine less accessible during leaching, leading to gold recovery loss. The tight temperature control requirement is a decisive factor in the choice of a Circulating Fluidized Bed (CFB) as the roasting reactor, due to the excellent mixing characteristics of the CFB which results in temperature homogeneity of (+/-10°C). Roasting of double refractory ores, as described above, can be included in the flowsheet after comminution and grinding, a process termed as whole ore roasting, or by including a flotation circuit termed as concentrate roasting. Roasting the flotation concentrate results in less solid flow, increased sulphide sulphur grade and organic carbon content resulting in a higher heating value and higher gold content. A typical composition of the Syama ore and concentrate is given in Table 1. Ore average values presented correspond to the period 2015, while concentrate values are typical for the flotation performance throughout the period 2012–2015."

Jan 1, 2017

By Alessandro Navarra, Roberto Parra, Boyd Davis, Frank Mucciardi

A smelter scheduling algorithm has been developed, which allocates the oxygen production between the smelting furnace and the converter aisle, so as to maximize copper throughput. The algorithm is intended for daily operation planning, controlling the sequencing of the converter cycles, and the oxygen drawn by these cycles. In some cases, it may be worthwhile to decrease converter oxygen allocation in favour of the smelting furnaces. Thus, a better utilization of the oxygen plant can increase primary copper throughput by several percentage points. This principle is demonstrated through sample computations. The approach presented in this paper can be incorporated into smelter management software.

Jan 1, 2015

By Lang Tao, Jun Wang, Wei Xiao, Wenqing Qin, Pan Cao, Guanzhou Qiu, Key Lab of Biohydrometallurgy of Ministry of Education, Central South University

"The effect of metal cations on the rutile flotation using styryl phosphoric acid (SPA) as the collector was investigated by micro-flotation test, bench scale flotation test, zeta-potential measurements and adsorption measurements. The micro-flotation results indicated that Fe (?) and Al (?) ions in low concentrations had obvious activation on the rutile flotation, and Pb (?) ions in low concentrations had smaller activation of rutile, but Fe (?), Al (?), Pb (?), Ca (?) and Mg (?) have strong inhibition of rutile flotation in high concentrations. The bench scale flotation results indicated ethylene diamine tetraacetic acid (EDTA), boracic acid, and sodium hexametaphospate can decrease the metal ions concentrations, and increase the recovery of rutile flotation. Adsorption measurements and zeta-potential measurements revealed that Fe (?), Al (?) and Pb (?) ions were adsorbed on the rutile surface, and had interaction with SPA. But when these ions concentration were over the largest adsorption capacity, residual metal ions could occur chemical reaction with SPA.INTRODUCTIONRutile is one of the favored minerals for production of titanium dioxide white pigment, primarily through the chloride manufacturing process (Stanaway 1994; Hou et al., 2013) However, the majority of rutile ores belong to refractory ores, while flotation is one of the most efficient methods to separate fine rutile from gangue (Dolbear et al., 1937). With the flotation development, many effective collectors were successfully applied in the oxide ore. Many reviews have indicated that organic phosphonic acid collectors showed good selectivity on oxide ores such as ilmenite and rutile (Bulatovic & Wyslouzil 1999; Liu & Peng 1999).It is inevitable that many types of metal cations are present in ore pulp. These metal cations significantly influence the flotation of minerals. Liu et al. (2015) showed that Ca2+ and Mg2+ could improve the floatability of spodumene at pH 12.5 and 10.0, respectively. The authors proposed that Ca2+ and Mg2+ ions readily form hydroxy complexes (CaOH(l) and MgOH(l)) and precipitates as (Ca(OH)2 and Mg(OH)2) in strongly alkaline solutions. Fan and Rowson (2000) investigated the effect of Pb(NO3)2 addition as an activator on ilmenite flotation and showed that it could improve ilmenite floatability. The addition of Pb(NO3)2 resulted in an increase of ilmenite zeta potential in both weakly alkaline and acidic aqueous solutions. Mehdilo, Irannajad, and Rezai (2015) studied three kinds of ilmenite of different origins and discovered that both Mg and V had a negative correlation with ilmenite flotation, while the Mn content seemed to correlate positively with flotation efficiency. A number of studies have also showed that Fe3+ can improve the floatability of ilmenite (Fan et al., 2009; Nuri, Mehdilo, & Irannajad, 2014)."

Jan 1, 2016

By Roland B. Hoag, Roger G. Webber

Sulphate concentration in groundwater is a good measure of the extent of oxidation of sulphides, provided that sulphide minerals are the primary source of the sulphate. A study was conducted near the Eustis Mine in Quebec to determine where and how the sulphate in groundwaters originated. Atmospheric precipitation is the only source of sulphate other than oxidation of sulphides, and in this study area it is equal to 0.01,. millimole per litre. The oxidation of sulphides can be divided into subsurface oxidation (mainly inorganic processes) and surface oxidation (including both organic and inorganic processes) . The maximum sulphate concentration due to subsurface oxidation of sulphides depends on the solubility of 0 2 in water and is 0.25 millimole per litre. Surface oxidation is, therefore, responsible for any amount greater than atmospheric plus subsurface contributions (0.29 millimole per litre). Surface inorganic oxidation occurs in waters with a pH greater than 15 and is controlled by the kinetics of the oxidation processes. Organic (bacterial) surface oxidation is dominant only in acid (pH< 1.5) waters. The bacterial action accelerates the oxidation of sulphides, and large quanttties of sulphate may be introduced into solution.

Jan 1, 1976

The Silvermines area of north County Tipperary in Ireland has experienced mining activity for over a thousand years, with lead, zinc, copper, barite and sulphur being extracted from a series of Carboniferous limestones. The last mine to operate in the area was closed in 1993. A legacy of contamination and derelict surface structures remain. Following the death of cattle in the vicinity in 1999, a governmental Inter-Agency Group was established to conduct an investigation. The ?Silvermines Rehabilitation Project? resulted, and included a proposal for the development of a Mine Waste Management Facility (MWMF) to act as a repository for waste materials from problematic sites across the area. The nature of the setting supported an effective solution from both a cost and performance perspective; and with limited maintenance requirements. Locating the MWMF where most wastes were identified would help minimise handling and relocation of materials. This position coincided with an area of artesian groundwater pressures. The resulting MWMF design consisted of a perimeter engineered embankment with the crest elevation designed to just exceed the groundwater piezometric surface. The base would remain unlined and groundwater permitted to rise up into and saturate the contained in-situ tailings deposits and imported mine wastes. The proposed system thus benefited from the ?wet cover? approach to minimising further oxidation of wastes and metal leaching, but without the usual accompanying outward hydraulic gradient and leachate management issues. A sub cap drainage layer with downstream outlet was incorporated to prevent any possibility of hydraulic rupture following an unexpected rise in groundwater heads. Leakage rates from the MWMF were deemed to essentially be driven by surface infiltration rates alone (characteristic of a ?dry cover? approach), with the proposed composite capping system simulated to perform at an infiltration rate of less than 1 mm per year. A toe drain was incorporated with the perimeter containment system, and this collection together with diverted neighbouring drainage was directed under gravity to a dedicated Passive Treatment System (PTS). Overall, effluent water quality from the PTS has been predicted to reflect an annual mass metals removal in the order of 95% below baseline.

Aug 1, 2013

By W. F. Scott, K. L. Somerville

"This paper outlines the development and inplementation of functional training at the Thompson Mine of Inco Metals Company, Manitoba Division. This training is an extension of similar methods implemented throughout the company to meet safety and health and productivity objectives. It consists of the orientation to the mine, induction in the basic mining skills, and specific training in drilling and other skills in the mine. Initial results indicated a positive effect on the safety performance and proficiency of the mine workforce.IntroductionThe primary mining method at the Thompson Mine is mechanized cut and fill, with secondary recovery of pillars by undercut and fill . These methods require a workforce of about 900 hourly operating employees to obtain capacity production of 6500 tons of ore per day.Historically, turnover of mine employees has been high and large numbers of new recruits are introduced to the mine every year. These men are recruited primarily in Manitoba, but also from distant areas of Canada; most of the se people have no previous mining experience.Training has always been an important component of mine operations. Mine supervisors and experienced miners have committed an appreciable amount of time and effort to training these new recruits. As well, training efforts have been directed toward upgrading the skills of experienced workers.Recently, a growing awareness of the significance of this training effort and its impact on accident frequency, productivity, turnover and other important parameters of the mine operation has led to a review of training methods. The training program described in this paper has resulted from this review."

Jan 1, 1981

By A. M. Salomon de Friedberg

"With respect to impurities, HBM&S&apos; copper smelter, located in Flin Ron, Manitoba, is in an unusual position. In addition to the usual concerns, the fact that copper and zinc production at Flin Ron is closely integrated results in the unique situation where feed to the copper smelter typically contains 7% to 8% zinc. This paper discusses the ramifications to copper smelter operations resulting from the marriage of HBM&S&apos; metallurgical plants. Distributions of impurities (specifically Zn, Pb, Ni, As, Bi, Sb, and Cd) are presented and operating practices designed to reduce the impact of impurities on anode copper quality are detailed.IntroductionHudson Bay Mining & Smelting Co. Ltd. (HBM&s), has been operating its metallurgical complex located in Flin Flon, Manitoba, since 1930. The smelter and zinc plant were originally separate entities with respect to production. The smelting operation consisted of traditional multiple-hearth roasters, a reverberatory furnace and Peirce-Smith converters. The zinc plant also utilized multiple hearth roasters and then followed with sulphuric acid leaching, purification and electrowinning. The zinc plant also recovered cadmium from a separate purification/electrowinning circuit.The two plants operated essentially independently of each other until rising zinc levels in the copper concentrate and large stockpiles of zinc-rich leach residues prompted the construction of the fuming plant in 1949. The smelter used pulverized coal to reduce zinc oxide present in the reverb slag and then captured the resulting zinc bearing fume in the fuming plant baghouse. The fume was sent to a separate ""oxide roaster"" in the zinc plant where it was first roasted to remove halogens and then leached to recover the contained zinc. This oxide fume became a major source of feed to the zinc plant accounting for roughly one quarter of the total zinc production. Furthermore, through the smelter&apos;s treatment of sulphide leach residue, both copper and zinc recoveries were improved for the over-all complex."

Jan 1, 1993

By L. C. So, S. Faucher, S. Mostaghel, D. Sauter, S. -Y. Oh, S. K. Lee

"Molten material from pyrometallurgical furnaces is tapped at high temperature, carrying a large amount of heat. Traditional handling methods of slow air cooling or water granulation do not allow for the recovery of heat from slag and matte. Furthermore, water granulation adds an inherent safety risk of explosions. Recently, there have been numerous studies into processes attempting to recover waste heat. However, most of them have never been commercialized due to numerous challenges including scalability, cost, low heat recovery efficiencies, and difficulties in heat utilization. Ecomaister-Hatch has recently developed and commercialized a reliable and simple dry atomization system that allows for heat recovery while eliminating the use of water. Comparisons of pilot and commercialized dry atomization and heat recovery technologies will be presented and challenges of these technologies will be highlighted.INTRODUCTION Slag has traditionally been regarded as an undesired waste product from smelting operations with slag management focused on removal and disposal of “waste”. Over 500 million tonnes of slag are produced per year, carrying with it ~220 TWh of energy (Barati, Esfahani, & Utigard, 2011). Depending on the process, the energy content of slag ranges from 10-90% of the total energy input (Barati, 2011, Rodd, 2010). There has therefore been great interest in recovering energy from slag. Slag handling methods can broadly be classified into three categories: (1) dumping and slow cooling, (2) wet granulation and (3) dry granulation. As discussed below, only dry granulation routes are amenable to heat recovery. Slag dumping involves the slow cooling of molten material and crushing of the resulting solid. In this process, slag is dumped on the ground directly from furnaces or transferred to slag pots that are moved by rail or haulers and then dumped on the ground. The molten material is left to cool and solidify until it can be broken and handled by heavy machinery."

Jan 1, 2017

By Sazol Das, Hany Ahmed, Ganesh Bhaskaran, Zhuoru Wu

"Friction stir welding (FSW) process in lap configuration for dissimilar materials has been developed and tested for steel to aluminum joining. A novel cylindrical tool was designed for improved material flow. The joining of steel to high strength 5xxx and 6xxx aluminum was carried out by FSW technique using optimized process parameters. The microstructure, micro-hardness, joint strength and corrosion properties at the weld interface have been investigated. Optical and scanning electron microscopy reveled a well layered structure at the interface and lap shear tests of the welds showed excellent fracture resistance. Neutral salt spray tests for up to 500 hours (ASTM B117) were carried out on the bare steel to aluminum FSW joints, which did not show neither evidence of corrosion at the weld interface, nor any degradation of the weld strength. The FSW lap configuration was applied to prototype commercial vehicle structural component whereby a steel stiffener insert was friction stir welded to high strength 6xxx aluminum alloy. The interface microstructure showed layered root without any steel shattering in aluminum side. A finite element study was carried out to quantify the benefits where it was found that the stiffness increases by 76% under bending loads and 36% in torsion loads.INTRODUCTION Energy preservation and environmental issues, namely carbon footprint and legislation around emission in transportation industries has led to a growing need to use of lightweight materials such as aluminum and magnesium alloys along with various grades of steel in structural application, while still maintaining their strength and crashworthiness. Assembling dissimilar materials within integrated structure is thus a stringent requirement related to optimum performance. In order to achieve an efficient technology of joining dissimilar materials such as aluminum to steel, it remains difficult to select an effective welding process for a given joint configuration. The use of aluminum in transportation industries for structural component is not exclusive in a design and is almost always used along with various steel grades for a mixed materials solution, thus dissimilar aluminum/steel lap joining is of great interest since this is widely used in the assembly of parts (e.g. pillar, frame rails, chassis, body in white (BIW), CAB, etc.)."

Jan 1, 2018

By V. I. Ryaboy, S. A. Kondratyev

"The paper describes influence of desorbed species (DS) of a number of xanthates and higher dialkyldithiophosphates on the collective ability of these reagents. Adsorbed on mineral DS of the reagents in the form of products of non-stoichiometric interaction between xanthates and heavy metal salts can pass to the gas–liquid interface and remove liquid from the layer between mineral particle and water surface. A high-speed video recording displays the process of spreading of DS of xanthates and dialkyldithiophosphates over water at the moment of local rupture of the water layer. Expansion of “dry” spot on the mineral surface after DS of xanthate capture and displace liquid from the layer has been proved with video images. The comparative analysis of collecting ability and dynamic surface activity of dialkyldithiophosphates shows that these characteristics are in good correlation. The forces exerted by spreading film of the reagent’s DS on liquid in the water layer are evaluated, and the water flow rate from the layer is determined. The line of the reduction in thickness of the water layer behind the front of spreading film of DS of dialkyldithiophosphates and xanthates coincides with the line of the increase in their dynamic surface activity. Their force on the liquid volume in the water layer characterizes collecting ability of the DS film of xanthates and dialkyldithiophosphates. It has been supposed that the collecting ability of DS of a reagent is a part of its overall flotation activity, conditioned by surface tension of solution and, thus, defined by the structure of hydrocarbon fragment of the reagent.INTRODUCTIONIt is believed that collecting ability and selectivity of collecting reagents is mainly governed by adsorption of a reagent at the solid–liquid interface. A few studies have shown that activity of collecting reagents at the gas–liquid interface may have deep influence on their collecting capacity and selectivity. Experimental researches have revealed correlation between surface pressure in a carboxylic acid film on liquid’s free surface and floatability of useful components (Kulkarni & Somasundaran, 1975; 1980; Quast, 2006). According to Quast (2006), it is not always that surface pressure of a reagent film influences collecting ability of carboxylic acid. For instance, pH range of adsorption of tetradecanoic acid on hematite does not coincide with pH range of high surface pressure. So, surface properties of this acid contribute little to flotation efficiency.The correlation between reagent film surface pressure and mineral floatability has been reveled for quartz and cationic reagents, too (Bleier, Goddard, & Kulkarni, 1977). Finch & Smith (1973) showed that combination of adsorption of ion–molecular amine complexes on mineral surface and high surface tension of “fresh bubbles” was favorable for flotation performance. The use of bubbles with reduced surface tension resulted in a decrease in quartz floatability."

Jan 1, 2016

By R. White, C. Doyle, B. Martin, C. Díaz, J. Hrepic, G. Cuthbert

"A program initiated to improve the service life of the magnesite-chrome refractory in the top blown rotary converters at INCO’s Copper Cliff Nickel Refinery identified slag corrosion as a major wear mechanism. Target slag compositions were established to produce a non corrosive slag. A plant program to achieve this target slag by the addition of controlled amounts of do lime and MgO was instituted. Addition to rates of the slag modifiers was optimized based on the slag composition assays achieved and the requirement to address corrosion effects on the high alumina content ladle refractory. A60% gain in TBRC refractory performance was eventually achieved and has been maintained yielding a net annual savings of $700,000. A significant gain in available converter operating time has also been realized.IntroductionINCO’s Copper Cliff Nickel Refinery utilizes two top blown rotary converters (Fig. 1) to smelt a blend of semi-refined nickel concentrates, producing a granulated nickel matte suitable for the adjacent carbonyl based nickel refining operation. The converter, or TBRC, operation is a batch process composed of feed charging and melting, oxidation of the excess sulphur in the matte, and reduction of residual nickel oxide. The final matte, containing about 78% nickel, is tapped at 1600°C from the converter and is granulated in a sluice equipped with high pressure water jets."

Jan 1, 1997

By A. M. Salomon de Friedberg

With respect to impurities, HBM&amp;S&apos; copper smelter, located in Flin Flon, Manitoba, is in an unusual position. In addition to the usual concerns, the fact that copper and zinc production at Flin Flon is closely integrated results in the unique situation where feed to the copper smelter typically contains 7% to 8% zinc. This paper discusses the ramifications to copper smelter operations resulting from the marriage of HBM&amp;S&apos; metallurgical plants. Distributions of impurities (specifically Zn, Pb, Ni, As, Bi, Sb, and Cd) are presented and operating practices designed to reduce the impact of impurities on anode copper quality are detailed.

Jun 1, 1993

By Andrew Dobson

The assessment and control of environmental noise from mines has become increasingly important in recent years, due to urbanization and population growth, increased regulation of environmental factors, and overall awareness and sensitivities to noise exposure.&nbsp;Minimizing adverse effects on communities and achieving compliance with local ordinances is now commonplace, and consideration of noise during the design and/or operation of a mine cannot be ignored. Ventilation equipment can represent the loudest and most bothersome equpiment at mines, however there are complexities when attempting to control the assocaited noise, due to the acoustical nature of&nbsp;mine vent fans. In fact, the utilization of traditional and/or&nbsp;industry standard methods can intensify&nbsp;the noise impact, or simply not work as intended. This paper provides recommendations on specific noise control methods that are suitable for mine ventilation equipment, based on recent assessment work and field experience.

Oct 1, 2024

By D. F. Machuca-Mory

The new algorithm for high-order simulation of ore deposit grades termed HOSIM is based on the concept of spatial cumulants. The algorithm is tested using data from Apensu, a structurally controlled gold deposit in Ghana. The required high-order spatial structures are obtained from a training image or analogue of the deposit. Using the available drillhole data and training image, HOSIM realizations are able to model well the grades and geometry of the large and well sampled mineralized structures. However, under-sampled small structures remain difficult to model. HOSIM offers a promising alternative for the spatial simulation of complex non-Gaussian orebody attributes of interest.

Jan 1, 2011

By Dale C. H. Nevison

One of the most intensive of material rivalries is the confrontation between zinc die castings and plastic injection moldings. Pressed hard by the plastics industry, zinc die casters are learning how to make parts with less material yet without sacrificing quality. The key to this new trend is the technique of Thin Wall die casting. The obvious benefits of Thin Wall are lighter weight and lower cost. Again, obviously, these are the very selling points that put plastics into many appliance and automotive parts formerly made of zinc. One of the factors that has been most conducive to the outstanding growth of plastics has been the increasingly prevalent concept that "adequate" properties are sufficient, especially if there are cost advantages. Most of modern design today is oriented around the reasonable life of a product, rather than indefinitely extended life. This is simply an acknowledgment of the existence of a design environment that pervades many areas, reflecting the life-cyclic desire for change. Too often, so-called "weight-saving" materials end up being very costly - not only in production, but in durability and dependability. Change for the sake of change usually doesn&apos;t effect a change for the better. In the majority of cases, the best bet is to design in traditional materials and minimize the material needed, while maximizing the efficiency of the production process. Component prices of products to be produced from either plastics or zinc must be studied in detail to determine which material will produce the lowest cost of manufacture. It is not uncommon for two parts, similar in appearance at a casual look, to have a considerable difference in energy requirements and production costs. Detailed cost estimates of the advantages of each material should therefore be prepared for zinc and plastic parts before the final design and material selection decisions are made.

Jan 1, 1978

By J. E. Nesset

Significant progress has been made over the past few years on characterizing and understanding the hydrodynamic properties of frothers and collectors and their effect on flotation performance. This new understanding of the relationship between chemistry and hydrodynamics has dramatic implications for how flotation circuits should be controlled and optimized. Previous work has shown that choosing a frother of the right &apos;strength&apos; is critical to the optimization process, and the work and discussion presented here serve to strengthen the argument. In addition, we know that collector chemistry may also influence hydrodynamic properties and needs to be taken into consideration. To achieve the desired outcome, the overall system of reagents and operating parameters must be considered. This paper describes and discusses some of the findings from recent research on frother and collector chemistry effects (on hydrodynamics), and how this knowledge can be used to improve flotation performance. Examples from plant experience are discussed.

Jan 1, 2009

By M. Pearson, W. Bristowe, A. Hanson

"There&apos;s no such thing as quality assurance; only quality control ... by inspection. "(1) A common misunderstanding in the procurement and construction of custom designed, fabricated pressure vessels and piping systems is that quality assurance can be achieved by simply referencing codes, standards, ISO 9002, QMS or other such programs in the contract documents. In the authors&apos; experience, nothing could be further from the truth, not detrimental to the performance of the equipment than the exclusion of inspection activities and reliance upon warranties and "fit-for-purpose" clauses. Likewise, the expectation that fabricators, suppliers, or third party inspectors can provide such assurances is also unrealistic where they have limited knowledge of the process, material selection criteria, or limited technical resources. The development and successful execution of a quality assurance program is a collaborative effort by engineers, designers, material suppliers, equipment fabricators, and field inspectors with the full understanding and support of the end user.This paper presents an outline of the quality control activities undertaken by the authors for several recently completed and on-going hydrometallurgical projects. The activities include: prequalification of fabricators and sub-vendors, shop audits, material validation testing, material source control and verification, positive material identification of weld metal overlay, specialised welding inspection, contamination control for titanium and titanium-clad fabrication, eddy current and mass spectrometer (helium) leak testing of shell-and-tube heat exchangers, hot cycle testing of titanium clad equipment, tolerance verification for refractory lined equipment, final inspection and cleaning.

Jan 1, 2004

By N. J. Contini, R. W. Knopp

"In March 1988, old Denver flotation cells were removed from Dickenson's Arthur w. White Mill, and a new flotation circuit, consisting of four Prochem rougher cells and a Hydrochem agitated cleaner column, was commissioned. The refractory portion of the gold in the ore is associated with arsenopyrite, therefore the flotation circuit is set up to produce a saleable sulphide concentrate. Tailings from the leach circuit are conditioned prior to being pumped as feed to the flotation circuit. The prototype Hydrochem agitated column has been in operation as a single cleaner stage for rougher concentrate. The effect of flotation circuit changes on gold recovery data, as well as cleaner concentrate production, and development work to achieve the target results, have been investigated. Flowsheet modifications and the resulting circuit performance data, along with test results to date, will be presented.INTRODUCTIONThe mill is capable of treating 1000 stpd of ore averaging approximately 0.30 oz/ton Au. The ore is crushed and ground to 75% - 200 mesh. Gravity concentration, cyanidation, and Merrill - Crowe precipitation yields 84% gold recovery. Detailed descriptions of the comminution, gravity separation, and leaching circuits, as well as background information have been presented elsewhere (Suttill, Van Weert et al). The target cleaner concentrate grade is 1.0 oz/ton Au for custom smelting and refining. Historical gold recovery values of the old circuit was approximately 20% of the gold present in the float feed at the target grade. The recovery value objective set for the new circuit during the planning stages was 50% of the gold present in the flotation feed at 1.0 oz/ton Au in cleaner concentrate."

Jan 1, 1989

By Robert L. Tremblay

Dans le but de voir si une région comme la Gaspésie, qui a subi la derniere glaciation , se prête avantageusement à la méthode de prospection alluvionnaire, environ 800 concentrés de minéraux lourds furent prélevés dans les districts électoraux de Matane et de Gaspé-Nord. Les différentes phases minérales présentes dans les concentrés ont été examinées à la loupe binoculaire. Afin de mieux valoriser ce type d&apos;inforrnat ion, nous avons été arnenés à expérimenter et à mettre en oeuvre des techniques multivariables adaptées au traltement d&apos;une information semi-quantitative en utilisant le principe d&apos;un codage logique préalable. La structuration des résultats de la Gaspésie a conduit à l&apos;élaboration de cartes de synthèse qui constituent un support nécessaire à l&apos;interprétatlon des répartitions plus ponctuelles des minéraux "utiles" sur le plan de la recherche minière.

Jan 1, 1978